The triceps take up about 2/3 of the upper arm, and seem to be one of the first places many women put on extra fat in the upper body.
So as others have said, watching your diet to reduce overall body fat is important, BUT you can target the area with weights and resistance work (you can't spot reduce fat, but you CAN spot increase muscle).
Kickboxing/boxing is good for that area. And once you get good with the punches (not before!) you can add resistance in the form of weighted gloves and/or bands. (I posted some advice on weighted glove use in my blog, since the question comes up from time to time:
http://thecathenation.com/forum/blog.php?b=274 )
I just got this thingy to change up my boxing/kickboxing workouts (I've used weighted gloves for years, and do most of my KB/B workouts with them) :
http://www.heartlandamerica.com/bro...=89B8DB20-FD8E-4C79-AD5A-7AFACD9C9550&DL=QSP1
Not worth $100 (!), but definitely, IMO, worth $29.99. Use the same gradual progression for this as for weighted gloves. You could start with doing punches 1/2 time while wearing it, for a few minutes every few days.
HTH!
Also, Carmen, curling your arm would make the bicep pop. To get the triceps to pop, you have to straighten your arm and flex the triceps, like what this guy is doing in this photo:
Or this guy here: